Biolog-Eco法检测尸体微生物群落的代谢功能变化

目的检测死后不同时间尸体上微生物群落功能多样性的变化并评估其在死亡时间推断中的应用价值。方法采用Biolog-Eco微平板对野外实验中来自于死后0~240 h猪和人尸体的肛门拭子进行微生物群体的培养,监测其引起的光密度值变化,结合法医病理学及蝇类演替,观察自然腐败尸体微生物群落的代谢特性及其变化。结果微生物代谢功能多样性与蛆虫数量变化呈负相关关系。冷冻在0 h对每孔颜色平均变化率影响最大,48 h后基本消失,192 h后尸体微生物群落多样性相对不稳定。主成分分析将31种碳源综合为5个主成分(累积贡献率90%)。碳源tsquare分析显示,N-乙酰-D-葡萄糖氨和L-丝氨酸是推断人和猪样品PMI(0~240 h)的优势碳源。结论 Biolog-Eco法能表现死亡后0~240 h尸体上微生物群落对部分碳源利用的代谢差异,有望为死亡时间推断提供新依据。

Detection of Metabolism Function of Microbial Community of Corpses by Biolog-Eco Method

Objective To detect the changes of microbial community functional diversity of corpses with different postmortem interval(PMI)and to evaluate forensic application value for estimating PMI. Methods The cultivation of microbial community from the anal swabs of aSusscrofaand a human corpse placed in field environment from 0 to 240 h after death was performed using the Biolog-Eco Mi-croplate and the variations of the absorbance values were also monitored. Combined with the technology of forensic pathology and flies succession, the metabolic characteristics and changes of microbial commu-nity on the decomposed corpse under natural environment were also observed.Results The diversity of microbial metabolism function was found to be negatively correlated with the number of maggots in the corpses. The freezing processing had the greatest impact on average well color development value at 0 h and the impact almost disappeared after 48 h. The diversity of microbial metabolism of the samples be-came relatively unstable after 192 h. The principal component analysis showed that 31 carbon sources could be consolidated for 5 principal components(accumulative contribution ratio >90%). The carbon source tsquare-analysis showed thatN-acetyl-D-glucosamine andL-serine were the dominant carbon sources for estimating the PMI(0=240 h)of theSusscrofaand human corpse.Conclusion The Biolog-Eco method can be used to reveal the metabolic differences of the carbon resources utilization of the microbial community on the corpses during 0-240 h after death, which could provide a new basis for estimating the PMI.